Problem: $ { \left[\begin{array}{rr}{4} & {-1} \\ {4} & {-1}\end{array}\right]-\left[\begin{array}{rr}{0} & {4} \\ {-1} & {0}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{4}-{0} & {-1}-{4} \\ {4}-{-1} & {-1}-{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{4} & {-5} \\ {5} & {-1}\end{array}\right]}$